Telephone exchange system



Feb. 14, 1933.

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TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 16 Sheets-Sheet 16 D HmnM 1650 i VA @E f E@ IHIHIHIIIH IIHHHIHIH Lgt] /N VEA/TOR BY W. B. 5 TR/C/(LER A TTORNE y IH'II Patented Feb. 14, 1933 UNITED STATES PATENT OFFICE WALTER B. STRICKLER, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO BELL TELE- PHONE LABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK TELEPHONE EXCHANGE SYSTEM Application led March 1S, 1932.

This invention relates to dial switching telephone systems and more particularly to a central oliice sender of the so called decoder type for enabling operators at dial switching A switchboards to control the establishment of connections to any subscribers line or to an operators position in the exchange area.

The decoder type sender such as is disclosed for example in the Patent to Raymond and Scully, No. 1,862,549, granted J une 14, 1932, comprises a sender having ofiice code registers for recording the oiiice code and numerical registers for registering the numerical digits of desired connections, apparatus `for controlling the setting of panel type selector switches and apparatus for transmitting series of code impulses for recording desired line numbers either in recording apparatus at a terminating manual operators position or in a sender at a tandem dial switching ofiice. For translating the oilice code digits registered in a sender of this type into the proper combination of registrations for controlling the setting of selector switches for routing a call to the proper office, a plurality of decoders is provided common to a plurality of senders. An idle one of these decoders is seized following the seizure of a sender and the oiiice code registered in the sender is then transferred to the associated decoder where the necessary translation is made and a routing relay is operated which determines the routing of the desired connection. In accordance with the particular routing relay operated control registers in the sender are selectively operated and the decoder is then dismissed. rlhe operated control registers in conjunction with the numerical registers of the sender then determine the Vsetting of selector switches or the transmission of code impulses for controlling the completion of the desired connection.

In accordance with the present invention the A operator has access to trunks of different character over which she may control the termination of desired connections. Certain of these trunks terminate in district selectors, others in incoming selectors, still Serial No. 599,684.

automatically associated with a sender whichv is then capable of recording the designation of a desired connection under the control of a keyset at the operators position.

If, for example, the operator should desire to terminate a toll connection in which case it would not be necessary to operate a district selector or an ofice selector, she would plug into a trunk circuit of the type terminating in an incoming selector and would record in the sender only the numerical designation of the wanted line. Since in this case no oiiice code digits are recorded in the sender no translation is required and therefore it does not become necessary to associate a decoder with the sender. It is therefore an object of the invention to economize in the use of a decoder by eliminating it from all calls where its services are not required. This object is realized in the present invention by the transmission of a discriminating signal to the sender when the sender is seized from a trunk circuit which terminates in an incoming selector, which signal prevents the attachment of a decoder and so modifies the,r

sender circuit that the numerical digits keyed by the operator will be recorded directly on the numerical registers of the sender and the usual district and office selector controls exercised by the sender will be omitted. l

If the operator should desire to terminate a connection over a route through av full mechanical tandem office she plugs into a trunk circuit of the type terminating in a district selector at the tandem oflice in which case a different discriminating signal is transmitted to the sender. Since in this case the selectors in the tandem office are to be set rfrom the tandem sender it is not necessary to make a translation at the operators sender mitted to the tandem office in accordance with '959 provision vis made for advancing the trunk circuit to a reorder position whereuponfthe operator is signaled'that she has made an ery `ror and her keyset is disconnected. 'She may 5fthen take -down the connection, plugV into g another trunk and repeat the call correctly. 1 Provision is also made for giving the operathe oiiice code and numerical registrations which the operator has caused to be set up v in the sender through-the operation of Aher keyset. Y Y v Should the operator have plugged into a. trunk terminatingin a distant oiice selector for calls to toll koperatorspositions a still dii'erent discriminating signal is transmitted to the sender to indicate to the sender that an `oliiilce code will'be registered therein requir- -ing translations. In-,this` case a decoder becomes associated with the sender and since no district selections are necessary-the circuits of the sender are modified to pass overV the'districtselections'. Y v Should the operator have pluggedinto a sender functions in the usualmanner to associate a'decoder. Vandto thereafter function to control the setting; of the ldistrict selector and oliice selector, if required, andvincomingv and iinal selectors of if the'call is to terminate in a manual oiice, to` cause the setting of f district and otiiceselectors to extend the connectionftothe desiredoiceand to then transf 0, mit codes of impulses under the control of the at the distantv manual operators position the number of the desired line.

-Thesetting of the'fregisters of thesender is1accomplished substantially the same granted Novemberll, 1930 to W. W. Carpen- 'ter and I-lersey.;V That is, impulses of light or heavy negative `or positive current `are transmitted over the" tip orL ring or over both tipY and conductors of theop'eratorsl cord circuit and the trunk toV which she `makes connection to a group ofrecording rei i A operators switchboard positlon, hasaclaysin the sender. Should the operator plug into a trunk terminating in an incoming selector, sheV should key butour digits on'A her'A keyset asin this case only incoming and final selectorsmust be setto terminate thedesiredconnectionA However, should she through Y error key more than the required 'four digits,

f tor a reorder `signal and for disconnecting '-,her keyset-if she has plugged into a trunk to -a tandem oiiice,fii:l she'rhas plugged vinto a ,trunk toa distantpiiice selector, or into av trunk terminatingVK in a local district selector" i"and keys incorrectly.,`

Other features of the invention tion taken in connection withy the attached f drawings in which Fig. 1 shows an operators cord circuit for anlslwering special service and intercepting ca s; l

Fig. 2 showsthe' operators telephone and keyset circuits; e A l F ig. 3 shows an outgoing trunk circuit which may terminate in a local incoming selector, inthe district selector of za. distant tandem cnice, or in a distant 'office selector and the schematic representation of an 1ncoming' and a final selector and called subscribers line and a sender selector for con*- necting the trunk circuit withan idle sender;

Figs l to v1 5 inclusive, show v.the circuits of Y a'sendenFig. 4 showing thecountingrelays e for controlling the setting 'of selector switches `in, acocrdance withk digits registeredjin the l sender and other control relays;

' Figs.r5, 6, 7, 9, 10 and ll'show registers for registering ,digits keyed 'by the operator and additional control relays; Fig. Y8 shows an impulsing switchfor transmitting code impulsesin accordance with registereddigits orsetting cal-l indicatorapparatus ofmanual oiiices, or registering apparatus of tandem senders in tandem oiiicesto n Y' which a connection may be established numerical vregisters of the sender'to record Y FigsQlt and lrshowthe selection control- 'ling registers and. additional Y controly relays; manner as disclosed in VPatent No. 1,780,906',`

' sender finder for connectingy the trunk circuit franged to show the complete'circuit.V f

The cord circuit of Fig. 1, located atthe tion withthe A switchboard operatospsition orthepurpose' of obtaining the assist- Errance ofthe operator in 'completingftoll or other calls. VThe operators telephone set and keyset of Fig. 2 are common to all cord clrcuits such as that shown in Fig. l of the operators position.. Through the cord circuit ofFig. l the operator has access to aiplurality of groups kof outgoing trunks,"for eX- ample, the trunks of one group, of which the trunk circuit of Fig. 3 may be 'one,ter" kminating lin incoming selector yswitches for terminating toll calls ,f the trunks of a second group terminating in the loiceselectors v will be apl i parentlfrom the following detailed descripof adistantoiiice; the trunksof a third group terminating inthe district selectors of a disico tant tandem oiiice and the trunks of a fourth group terminating in local district selectors as disclosed in Fig. 16 and more particularly in the application of J. B. Newsom, Serial N o. 599,611, filed March 18. 1932. The trunk circuits of the first three groups are all similar except for a slight difference in wiring for indicating the group in which thel trunk seized by the operator is located for the purpose of guiding the sender in its functions as will be hereinafter explained.

The sender disclosed in Figs. 1 to 15 inclusive, is similar in general to the sender disclosed in the patent of Raymond and Scully hereinbefore referred to, but differs therefrom by the introduction of the novel features of this invention. This sender is arranged to operate in conjunction with the decoder and decoder connector disclosed in detail in the patent of Raymond and Scully, such decoder and decoder connector having been omitted from the present application for the purpose of simplifying the disclosure. The conductors extending to the left margins of Figs. 6 and 7 correspond with similar conductors shown in the Raymond and Scully patent for connection to the decoder connector.

Connectm?, 250 trunk terminating n am, incomng Selector It will first be assumed that an incoming connection is extended in any well known manner to the trunk jack of Fig. 1 and that the desired connection may be completed over an incoming and final selector switch. The operator upon noting the illumination of the lamp (not shown) associated with jack 100, inserts the plug 101 of the cord circuit shown in Fig. 1 into jack 100. A circuit is established from ground over the sleeves of jack 100 and plug 101 to battery through the winding of relay 102 and the winding of marginal relay 103 in series, and to battery in parallel therewith through the non-inductive winding 101 of relay 103. At the same time the trunk lamp is extinguished. Relays 102 and 103 both operate over a low resistance ground connected to the sleeves of trunks employed for special service and establish a circuit for the supervisory lamp 105 extending from battery over the inner contact of relay 102, resist-ance. 106, back contact of relay 107, back contact of relay 108 to ground through lamp 105 and in parallel therewith from battery over the inner contact of relay 102, resistance 106, back contact of relay 107, back contact of relay 108, inner lower back contact of relay 109, inner normal contacts and winding of relay 110 to ground at the lower right normal contacts of key 111. Relay 110 locks in a circuit from battery at the inner contact of relay 102, inner upper alternate contacts and winding of relay 110 to ground at key 111.

As soon as plug 101 is fully inserted, relay 107 operates in a circuit from battery, ballast lamp 112, upper winding of relay 107, lower front contact of relay 103, lower left winding of repeating coil 113, lower normal contacts of key 11e', rings of plug 101 and jack 100 and returning over the tips of jack 100 and plug 101, upper contacts of key 114, upper left winding of repeating coil 113, inner upper front contact of relay 103, lower winding of relay 107, to ground through ballast lamp 115. Relay 107 operates and a flashing shunt circuit is thereupon established for lamp 105 until the operator throws key 111 to the right to unlock relay 110, which circuit may be traced from ground through lamp 105, back Contact of relay 108, front contact of relay 107, lower front contact of relay 110 to ground at the contacts of interrupter 116. In case, however, relay 107 operates before relay 110 can operate, lamp 105 does not light. The possible flashing of lamp 105 as above described is incidental and has no significance. at this time.

Then the operator throws her key 111 to the right or talking position, an obvious circuit is established from ground over the upper right contacts of key 111 for relay 117 which establishes a circuit from ground at the upper front Contact of relay 103, inner upper front contact of relay 117, conductor 118 to battery through the upper winding of relay 200. Relay 200 operates and a talking path is thereupon established from the upper right winding of repeating coil 113, inner upper right contactsof key 111, conductor 119, upper contact of relay 200, right winding of repeating coil 201, condenser 202, lower contact of reiay 200, conductor 120, inner lower right contacts of key 111 to the lower right winding of coil 113. Assuming that the operators telephone set 203 is plugged up, the talking path just traced is inductively associated therewith through the left winding of repeating coil 201 and the operator is thereupon enabled to converse with the calling subscriber to ascertain information concerning the desired connection.

It will be assumed that the desired connection is of a character which can be completed over incoming and final selector switches and that therefore the operator first tests for an idle trunk of a. group terminnating in an incoming selector switch b touching the tip of calling plug 121 to the sleeve of the jack of a. trunk of that group. If the trunk is busy there will bebattery potential on the sleeve and this potential will be transmitted over the tip of plug 121, the

upper normal contacts of relay 122, the inner l upper back contact of relay 123, the upper normal contact of key 124-, conductor 125, condenser 204 to ground through the lower right winding of repeating coil 205 which induces the busy potential through the left GQ'windingsorepeatingcoil 113 and 'connects '41 i raras winding of :coil 2 05 into the V operators tele- 'phone set thus'producing a clickin herk receiver,` Assuming that shetests the trunk lcircuitfof Fig; 3 and iin'ds it idle and receives ,no'clicln she inserts theplug121 into jack 300 thereby establishinga circuit extending 'from ground at the upper back contact of relayr302, 'the upper back "contact of relay -K 303, winding of relay-304, sleeves of jack 300 land'plug 121, windings of relay 126 ,and marginal relayr 127 in series to battery and -in parallel through resistance '123 to battery.' Due tofthe'presistance of sleeve "relay 304 of', the trunk Vcircuit sunicient `current flows ,throughfthe winding .of relayv 126 to cause its operation, but marginal relay 127 V-'does not operate@ Relay 304 closes an obvious circuit for relay 3 03 which at its upper front contact connects battery through resistance 338 to the sleevev of jack'300 for maintaining abusy condition on the sleeve in case' of a premature discon` neet andcloses at its lower `rontcontact apart of the' circuit'for'the Lall-trunks busy Ylamp 322.` 'l

` Relay 126 upon operating closes a circuit extending from battery joverlits lowerV con` tact, thelower normal contacts of key 124 to ground through the winding of relay 123 which. operates, opening the busy test cirQ' cuitat its upper back contact and at its inner upper and inner lower `front contacts con- V'nec'tsthe tipand ring contacts ofplug 121 to thel right Vwindingsfof repeatingfcoil 113i.

.Relay 12@ at its lower front contact also esf tablishes a circuit (for lamp 129 extending l vover theupper b aclrfcontact of relay 130.

Preparatory to keying the digits necessary to 'complete-the connection, the operatorY now depresses the key206 and, with the'` talking 4key 111v operated to the fright, a circuit is esytablished from ground at the lower back contact of relay 208,1,thegright contacts `oiflrey 206, conductor 207 ,fthe lower and upper in- "termediate `alternate contacts of key 111, the

Vupperwindingiof relay l122 'tojbattery at the jlower contacter relay 123.1; `Relay 122 thereupon operates 'and-'loels in a circuitvfrom .Y x'battery'overfthe lower contact oi/relayv 1,23,

lower winding and inner front contact of rev lay 122, conductor 131, backcontact offrelay 209 Vandfin parallel to groundthrough resistan'ce, 210 and the windingfof relay 208. Relay 208 operates in this circuit opening the initial .operating circuit of relay. 122 and clos- 'ing an: obvious circuit 'for relay 211 whichV operates; :Relayi122'at-its upperand lower f' alternate S contacts disconnects Vthe tip and "ring contactsv ofplug 12,1 from the right 1these contactsfover conductors 132and 133 l"with the operators keysetcircuit.

vRelay 211 upon operatingjclosesan obvious o circuit tolight 1amp212,fconnects ground over conductor 213 forgsu'pplying'operating igvound th keys Yf'theikeyset 214 and establishes a, circuit -from ground at its up'- per vcontact through the windingY and vupper Anormalcontacts of relay 215, conductor 1:32 upper alternate contacts of relay, 122, tips 4of plug 121 and jack 300, upper back contact of relay 307, lower back contacter relay -306 to battery through thejwinding of re,- Vlay 305. Relay v305 operates in this circuit, u

but relay 215 being marginal does nobr@ ceive sufficient current to operatey at this time 310, llower back `Contact of relay 307, upper "85 .back contact ottest relay 311, inner lower backy contact of relay 312 to ground latthe upper contact of relay308. At its lower-v most contacts relay 309fconnects the two lower:

windings of testjrelay 311 in a series circuit extending from battery, through the middle *winding of relay 311,'the lowercontactsolc relay 309, the lower windingof relay 311,'in-

ner `lower back contact 'of relay 312 toground at the upper contacter relay308 thereby preparing marginal relay.311 for operation and vconnects the ntest brush 313 `of sender selector 350` over thef'lower contacter relay308, the upper winding of test relay 311, thelower contacts ofrelay 309, lowerl winding ofre- "lay, 311 thence lto ground at the upper taet relay` `303.

p, Seizure-0f cile'svenoer It 'will 'niet be assumed that meander '105 upon the terminals of which [the brushes/:fof

selector 350 are at the time standing'is'bulsy and-that no koperating circuit "is therefore Vclosed forrelay 311.v 1A circuitfi's thereforeN t A closed forloperating the' stepping relay314 110 extending 'from'. battery, winding ,of relay 31,4, backl contact of ,magn et upperfront contact o'f'relay and tlience to ground overA the operating circuit of vrelay v309. o Ref,

lay 314'- operates connecting thewindingfot 115 lmagnet 315 to y,the operatingcircuit `of V relay 314whereupon-magnet 315-energ1ze`s in turn opening kthe circuit` of relay 314t which re-y leases opening ofrcircuitof magnet 315 which in. turnI releasesand thereby advances the 1.20.

brushes of switch 350 vone step. ln, this mannerV through the alternate operation and release of relay 314 and magnet 315 theV brushes of switch 350 are advanced step by ystep until ktest brush 313 vengagesI the terminal oran idle sender whenthe previously `traced cir- Vfc'uit through the upper andlowerwindings of test relay 311 tot-hetest brush 313 will be completed, for example, over conductor 316, inner right backcontactfof relay 1000,v 

